Combination locks, such as those for lockers, are known. Lockers in secondary schools and health club locker rooms may include a mechanical combination lock with a mechanical key override. The mechanical key can be used when a student or a user has forgotten his or her combination, and an administrator can use the mechanical key to both open the lock and reset the combination. Moreover, a school administrator uses the mechanical key at the end of a school year to open all lockers, to individually re-set all combinations, then records the new combinations of each locker. Many of these locks have mechanical key lock cylinders inside the lock which are either not accessible to rekey or very labor intensive to remove, rekey, and reinstall. The administrator must do so to ensure that the older students who were previously assigned a locker do not have the combination for the forthcoming years. This process is laborious, time-consuming, and expensive. Moreover, if the administrator key is lost, the locks must be re-cored or re-keyed. Other mechanical combination locks having mechanical override keys are known. See, for example, U.S. Pat. No. 9,222,283, assigned to the assignee of the present application, U.S. Pat. Nos. 6,877,345, 7,444,844, 7,628,047, 7,958,757, 8,234,891, 8,316,675, and U.S. Patent Application Publication Nos. 2009/0301147 and 2008/0307838.
U.S. Pat. No. 8,769,999 describes a mechanical combination lock, where a mechanical key can be used with the lock to identify the unlocking combination. While it primarily describes a mechanical key, in a parenthetical it mentions an electronically operated mechanism that can identify the unlocking combination. But it fails to disclose any structure whatsoever for the electronically operated mechanism or how it operates.
Electronically-operated locks, moreover, are known as well. U.S. Pat. Nos. 5,886,644 and 5,894,277, owned by the assignee of this application, describe electronic locker locks to fit a standard three-hole door prep layout as well as other doors. The electronic locks described in those patents comprise two housings, mounted at front and back of the door, and electronically connected through the center hole of the three-hole door prep layout, and they included an electromagnetically-driven latch, retracted automatically by the lock device when the proper code was entered by a user, either via a keypad or an electronic ID device such as an iButton®. U.S. Pat. No. 8,161,781 likewise discloses an electronically-operated lock to fit a standard three-hole door prep. All three patents are incorporated herein by reference.
U.S. Pat. No. 9,121,199 discloses an electronic combination lock that can be operated via touchscreen and also with an electronic key. The same access code is sent to the microprocessor to open the lock, regardless of whether the access code is entered via the touchscreen or input via the electronic key.
There is a need for a mechanical combination lock that can be opened by an administrator or manager with an electronic key of relatively inexpensive construction, particularly for lockers but with more versatility as to use on various standard designs, modularity as to assembly and opposite-hand use, easy programmability and convenience and simplicity to the user. It would be particularly advantageous if the mechanical combination lock required no battery storage within its housing, but still permitted an electronic key to override the mechanical combination and unlock it. These are the goals of the lock described below.